1. Field of the Invention
The invention relates to a drive device for moving the end fitting of a passive safety belt along a predetermined motion path which has in particular track sections extending at an angle to each other, by means of flexible tensioning means which can be driven, preferably by an electric motor drive.
2. Description of the Prior Art
In passive safety belt systems for motor vehicles it is known to make the end-fitting point of the belt movable in the motor vehicle along a track, in such a manner that before the person to be protected comes aboard, this end-fitting point is first located in the vicinity of the so-called A-post and with or after the boarding, is moved along the guide track into the region of the B-post. In this connection, drive devices, for instance in the form of flexible flat plastic belts or in the form of plastic jacketed steel cables, tensioning means are guided in continuous, correspondingly curved guiding tracks. These drive devices can be driven for instance, by electric motors, for instance by providing the flat plastic belt with a perforation which is connected to a seat driven by an electric motor. In both cases there is the disadvantage that when the tensioning means are driven, especially in the case of a push drive, the tensioning means buckles in the curved regions more or less strongly, which buckling together with increased friction between the tensioning means and the guide, makes it necessary to use a correspondingly strong drive.